Refactor to use plumber based on Highland streams

From now on, only support writing to directories, not individual files
No more dep on q or flatten
Correct dependencies
Fix tests
Merge pull request #3 from plumberjs/highland

Upgrade to plumber 0.3
0.3.0
Write data as raw Buffers, unless appending reference to source map
0.3.1
Update to use RxJS instead of Highland
Update deps and bump to 0.4
Merge pull request #5 from plumberjs/move-to-rxjs

Move to rxjs
Drop Node v0.8 from Travis targets
Ensure suffix is on a new line